Mechanical plating involves the formation of a coating from an oxidizing agent and a reducing metal in the presence of an impacting media. The energy used to form the plate coating is the energy of collision between the items to be plated and the impact media in the presence of the oxidizing agent and the reducing agent. Generally, mechanical plating is accomplished by the use of metal, metal salt or metal oxide powders. One of the problems associated with the use of powdered metals and metal salts is the pyrophoric and explosive tendencies of metal powders. This is especially true of easily oxidized metals such as aluminum, yttrium, magnesium, titanium and zinc.
Often during mechanical plating, organic chemicals, such as inhibitors and surfactants, are used. These chemicals may be toxic or evolve vapors which are irritating and/or hazardous to operating personnel.
It is desirable to eliminate the pyrophoric and explosive tendencies of the metal powders used in mechanical plating. It is also desirable to minimize exposure of personnel to toxic and/or irritating materials.
U.S. Pat. No. 3,328,197 issued to Simon relates to mechanical plating promoter chemicals which are an acidic material and a material which prevents agglomeration of the metal particles in aqueous suspension. The materials that prevent aglomeration of the metal particles include gum colloids, fatty acids or amines, substituted primary, secondary or tertiary amines or amides, polyoxyethylene adducts of various amides, higher alkyl trimethyl ammonium salts, long-chained ternary amines solubilized with ethylene oxide, amphoteric proteinaceous compounds and the like.
U.S. Pat. No. 3,460,977 issued to Golben relates to mechanical plating processes using certain surfactants. These surfactants include anionic or nonionic dispersants.
U.S. Pat. No. 3,479,209 issued to Clayton relates to mechanical plating process wherein the metallic particles are in an aqueous medium which contains a water insoluble oxygen-substituted lubricious aromatic compound having a relatively high volatility and a relatively low viscosity.
U.S. Pat. No. 4,389,431 issued to Erismann relates to mechanical plating process which uses a chemical promoter system. The promoter system comprises a flash promoter which is a strong acid or an acid engendering salt, a soluble salt of a metal which is more noble than the plating metal, a dispersant, and an inhibitor. The dispersant includes polyoxyethylene glycols, quaternary aliphatic ammonium salts, proteinaceous materials and the like.